HVOF deposition of TiC-based hardmetal coatings with High-Entropy Alloy (HEA) matrix

To provide wear-resistant substitutes to conventional WC-Co-based coatings for industrial applications, this work investigates the high-velocity oxygen fuel (HVOF) deposition of TiC-based hardmetal coatings with high-entropy alloy (HEA) matrices. The microstructural features, phase composition, and mechanical properties of four HEA matrix formulations, namely CrMnFeCoNi (“Cantor” alloy), Cr20Mn25Fe40Ni15, Al14(Cr20Mn25Fe40Ni15)86, and Al0.5CrCuFeNi2, coupled with 60 vol% TiC were evaluated. The HEA matrices contained a homogeneous distribution of TiC particles, according to microstructural examination, and the compositions incorporating Al had lower degrees of oxidation and decarburization. While the Cantor+60TiC and Al0.5CrCuFeNi2 + 60TiC coatings showed higher hardness and critical loads in mechanical tests, the Al14(Cr20Mn25Fe40Ni15)86 + 60TiC coatings showed more brittle behaviour. Discrete mechanical phases were identified by nanoindentation mapping and Gaussian Mixture Model analysis, and their hardness values were correlated with microstructural features. These findings underscore the potential of HEA-TiC hardmetal systems as wear-resistant coatings, particularly the Al0.5CrCuFeNi2 + 60TiC composition, which demonstrated superior oxidation resistance and mechanical robustness compared to the other formulations, and is free of cobalt. The insights gained will also serve as a foundation for AI-driven optimization of HEA compositions for targeted applications.